@article {9477, title = {Circulating Omega-3 and Omega-6 Fatty Acids, Cognitive Decline, and Dementia in Older Adults.}, journal = {J Alzheimers Dis}, year = {2023}, month = {2023 Aug 23}, abstract = {

BACKGROUND: Comprising nearly 35\% of brain lipids, polyunsaturated fatty acids (PUFA) are essential for optimal brain function. However, the role of PUFA on cognitive health outcomes later in life is largely unknown.

OBJECTIVE: We investigated prospective associations of plasma phospholipid omega-3 (ALA [18 : 3], EPA [20 : 5], DPA [22 : 5], DHA [22 : 6]) and omega-6 (LA [18 : 2], AA [20 : 4]) PUFA with cognitive decline, risk of cognitive impairment and dementia among adults aged>=65 years in the Cardiovascular Health Study.

METHODS: Circulating fatty acid concentrations were measured serially at baseline (1992/1993), 6 years, and 13 years later. Cognitive decline and impairment were assessed using the 100-point Modified Mini-Mental State Examination (3MSE) up to 7 times. Clinical dementia was identified using adjudicated neuropsychological tests, and ICD-9 codes.

RESULTS: Among 3,564 older adults free of stroke and dementia at baseline, cognitive function declined annually by approximately -0.5 3MSE points; 507 participants developed cognitive impairment and 499 dementia over up to 23 years of follow-up. In multivariable models, higher circulating arachidonic acid (AA) concentrations were associated with slower cognitive decline and lower dementia risk, with associations growing stronger with greater length of follow-up (hazard ratio [HR,95\% CI] of dementia per interquintile range, 0.74 [0.56-0.97] at 5 years, and 0.53 [0.37-0.77] at 15 years). Circulating docosapentaenoic (DPA) concentrations were associated with slower cognitive decline and lower risk of cognitive impairment (extreme-quintile HR, 0.72 [95\% CI: 0.55, 0.95]). Findings were generally null or inconsistent for other omega-3 or omega-6 PUFA.

CONCLUSION: Circulating AA and DPA, but not other PUFA, are associated with slower rate of cognitive decline and lower risk of dementia or cognitive impairment later in life.

}, issn = {1875-8908}, doi = {10.3233/JAD-230083}, author = {de Oliveira Otto, Marcia C and Wu, Jason H Y and Thacker, Evan L and Lai, Heidi Tsz Mung and Lemaitre, Rozenn N and Padhye, Nikhil and Song, Xiaoling and King, Irena B and Lopez, Oscar and Siscovick, David S and Mozaffarian, Dariush} } @article {9505, title = {Complexities of cerebral small vessel disease, blood pressure, and dementia relationship: new insights from genetics.}, journal = {medRxiv}, year = {2023}, month = {2023 Aug 13}, abstract = {

IMPORTANCE: There is increasing recognition that vascular disease, which can be treated, is a key contributor to dementia risk. However, the contribution of specific markers of vascular disease is unclear and, as a consequence, optimal prevention strategies remain unclear.

OBJECTIVE: To disentangle the causal relation of several key vascular traits to dementia risk: (i) white matter hyperintensity (WMH) burden, a highly prevalent imaging marker of covert cerebral small vessel disease (cSVD); (ii) clinical stroke; and (iii) blood pressure (BP), the leading risk factor for cSVD and stroke, for which efficient therapies exist. To account for potential epidemiological biases inherent to late-onset conditions like dementia.

DESIGN SETTING AND PARTICIPANTS: This study first explored the association of genetically determined WMH, BP levels and stroke risk with AD using summary-level data from large genome-wide association studies (GWASs) in a two-sample Mendelian randomization (MR) framework. Second, leveraging individual-level data from large longitudinal population-based cohorts and biobanks with prospective dementia surveillance, the association of weighted genetic risk scores (wGRSs) for WMH, BP, and stroke with incident all-cause-dementia was explored using Cox-proportional hazard and multi-state models. The data analysis was performed from July 26, 2020, through July 24, 2022.

EXPOSURES: Genetically determined levels of WMH volume and BP (systolic, diastolic and pulse blood pressures) and genetic liability to stroke.

MAIN OUTCOMES AND MEASURES: The summary-level MR analyses focused on the outcomes from GWAS of clinically diagnosed AD (n-cases=21,982) and GWAS additionally including self-reported parental history of dementia as a proxy for AD diagnosis (AD , n-cases=53,042). For the longitudinal analyses, individual-level data of 157,698 participants with 10,699 incident all-cause-dementia were studied, exploring AD, vascular or mixed dementia in secondary analyses.

RESULTS: In the two-sample MR analyses, WMH showed strong evidence for a causal association with increased risk of AD (OR, 1.16; 95\%CI:1.05-1.28; P=.003) and AD (OR, 1.28; 95\%CI:1.07-1.53; P=.008), after accounting for genetically determined pulse pressure for the latter. Genetically predicted BP traits showed evidence for a protective association with both clinically defined AD and AD , with evidence for confounding by shared genetic instruments. In longitudinal analyses the wGRSs for WMH, but not BP or stroke, showed suggestive association with incident all-cause-dementia (HR, 1.02; 95\%CI:1.00-1.04; P=.06). BP and stroke wGRSs were strongly associated with mortality but there was no evidence for selective survival bias during follow-up. In secondary analyses, polygenic scores with more liberal instrument definition showed association of both WMH and stroke with all-cause-dementia, AD, and vascular or mixed dementia; associations of stroke, but not WMH, with dementia outcomes were markedly attenuated after adjusting for interim stroke.

CONCLUSION: These findings provide converging evidence that WMH is a leading vascular contributor to dementia risk, which may better capture the brain damage caused by BP (and other etiologies) than BP itself and should be targeted in priority for dementia prevention in the population.

KEY POINTS: Do instrumental variable analyses leveraging genetic information provide evidence for a causal association of various vascular traits with Alzheimer{\textquoteright}s disease (AD) and all-cause-dementia? How do these associations compare for white matter hyperintensity (WMH) burden, a highly prevalent marker of covert cerebral small vessel disease (cSVD), stroke, and blood pressure traits, the strongest known risk factor for cSVD and stroke? Using Mendelian randomization (MR) leveraging large, published genome-wide association studies, this study showed a putative causal association of larger WMH burden with increased AD risk after accounting for pulse pressure effects, and some evidence for association of lower BP with AD risk with possible confounding by shared genetic instruments. Longitudinal analyses on individual-level data also supported association of genetically determined WMH with incident all-cause-dementia and AD, independently of interim stroke. This study using complementary genetic epidemiology approaches, identified increasing WMH burden to be associated with dementia and AD risk, suggesting the association as specific for cSVD and independent of BP and stroke.

}, doi = {10.1101/2023.08.08.23293761}, author = {Sargurupremraj, Muralidharan and Soumar{\'e}, A{\"\i}cha and Bis, Joshua C and Surakka, Ida and J{\"u}rgenson, Tuuli and Joly, Pierre and Knol, Maria J and Wang, Ruiqi and Yang, Qiong and Satizabal, Claudia L and Gudjonsson, Alexander and Mishra, Aniket and Bouteloup, Vincent and Phuah, Chia-Ling and van Duijn, Cornelia M and Cruchaga, Carlos and Dufouil, Carole and Chene, Genevi{\`e}ve and Lopez, Oscar and Psaty, Bruce M and Tzourio, Christophe and Amouyel, Philippe and Adams, Hieab H and Jacqmin-Gadda, H{\'e}l{\`e}ne and Ikram, Mohammad Arfan and Gudnason, Vilmundur and Milani, Lili and Winsvold, Bendik S and Hveem, Kristian and Matthews, Paul M and Longstreth, W T and Seshadri, Sudha and Launer, Lenore J and Debette, Stephanie} } @article {9913, title = {Circulating non-esterified fatty acids, risk of dementia and cognitive decline: The cardiovascular health study and multi-ethnic study of atherosclerosis.}, journal = {Neurobiol Aging}, volume = {148}, year = {2025}, month = {2025 Apr}, pages = {71-79}, abstract = {

Circulating non-esterified fatty acids (NEFAs) have toxic effects on a variety of organs central to cardiometabolic disease and can cross the blood-brain barrier. Whether NEFAs associate with cognitive decline or dementia remains unknown. Circulating total NEFA levels were measured in 3242 participants without dementia among older adults of the Cardiovascular Health Study (CHS) and related to adjudicated dementia over 6 years (n = 456 cases) and annually assessed cognitive decline. For confirmation, we related circulating NEFAs to cognition assessed 10 years later among 4361 participants in the Multi-Ethnic Study of Atherosclerosis (MESA). In CHS participants, each SD higher NEFA levels were associated with a hazard ratio (HR) for all-cause dementia of 1.11 (95 \% CI: 1.01; 1.22). Baseline NEFA levels were also associated with more rapid decline in cognition over 6 years of follow-up. In MESA, circulating NEFA measurements were associated with lower cognitive scores measured 10 years later.{\textquoteright}

}, keywords = {Aged, Aged, 80 and over, Atherosclerosis, Cognition, Cognitive Dysfunction, Cohort Studies, Dementia, Fatty Acids, Nonesterified, Female, Follow-Up Studies, Humans, Male, Middle Aged, Risk, Risk Factors}, issn = {1558-1497}, doi = {10.1016/j.neurobiolaging.2025.01.009}, author = {Moseholm, Kristine F and Jensen, Majken K and B{\r u}zkov{\'a}, Petra and Aroner, Sarah A and Fitzpatrick, Annette L and Longstreth, W T and Lopez, Oscar and Siscovick, David S and Kizer, Jorge R and Ix, Joachim H and Hughes, Timothy M and Hayden, Kathleen M and Nomura, Sarah and Tsai, Michael Y and McClelland, Robyn and Djouss{\'e}, Luc and Mukamal, Kenneth J} }